Fuse



July 14, 1925.

5 1,545,685 E. L. OGLE FUSE Filed Aug. 29 1921 2 Shoots-Sheet 2 557231; QyZey cheap and economical construction, which is the conductors Patented July 14', 1925.

entree STATES PATENT OFFICE.

ELMER L. O'GLE, OF CHICAGO, ILLINOIS, ASSIGNOR TO ELECTRIC COMPANY OF CHICAGO, ILLINOIS, A

CORPORATION OF ILLINOIS.

FUSE.

Application filed August 29, 1921. Serial mi. 498,207.

T 0 all whom it may concern:

Be it known that I, ELMER L. OGLE, a citizen of the United States, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Fuses; and I do hereby declare that the following is a full, clear, and exact description thereof, reference bemg had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

The invention relates to overload circuit breakers, commonly known as fuses, and consists of the matters hereinafter described and more particularly pointed out in the appended claims.

The invention relates primaril to a novel and improved fuse for use in mu tiphase circuits, which is adapted, upon an overload and resultant opening of the circuit of one phase, to open the circuit of the other phase or phases.

The object of the invention is to provide a novel fuse of the kind, which is of simple,

capable of being readily and easily conconnected in the circuits with which it is used and in which the fusible member or cartridge is capable of easy and quick removal or replacement after it has been burnt out.

These and other advantages of my invention will clearly appear as I proceed with my specification.

In the drawings- Figure 1 is a diagrammatic view, showing my improved fuse as applied and connected in a three-phase system;

Figure 2 represents a longitudinal section through the fuse;

Figure 3 is a perspective view of the fusible member or cartrldge before its insertion in the fuse;

Figure 4 is a cross-sectional view on an enlarged scale, the section represented being indicated by the line 44 of Figure 2;

Figure 5 is a longitudinal part section through the fuse in the plane of section of Figure 2, but on an enlarged scale;

Figure 6 represents a longitudinal section through the fuse in a plane at right angles to the plane of the section of Figure 2;

Figure 7 is a perspective view of the conductor bars, one cap, and the interior wiring of the fusible member or cartridge;

Figure 8 is an end view of the fuse;

Figure 9 shows perspective views of the open end of the fuse and of the associated cap or head carrying the knife blade contact, when in position to be applied to close said open end;

Figure 10is a view representing a side elevation of the fuse when connected in its circuit.

Referring now to that embodiment of the invention illustrated in the drawings: 10 indicates the improved fuse, which is of the knife blade t pef Three such fuses, 10, 10, and 10 are s own in the diagrammatic view of Figure 1, each connected in one of the mains 11, 11 11 of a three-phase system which are connected to a motor or other translating device indicated at 12. Each fuse contains a heating coil (to be more particularly described later) connected in multiple in shunt as illustrated) by conductors 13, 13; 13 13 13", 13 to another circuit 13, connecting the heating coil of the fuse 10' to the main 11; the conductors 13*, connecting the heating coil of the fuse 10 to the main 11 and the conductors 13 connecting the heating coil of the fuse 10 to the main 11. This is familiar practice with fuses of the kind.

Referring now to the novel fuse itself 14 indicates the body of the fuse and 15, 16 indicate the knife blade contacts at its ends. 17 indicates the enclosed fusible member or cartridge. The body consists of a heavy tube 18 of insulating material, such as fibre or the like, and of metallic tubular heads 19, 20, which carry the blades 15 and-16 respectively.

The one head 20 is permanently attached to the tube 18. The tubular part of the head closely embraces the end of the fibre tube 18,

i with its flat head engaged against a flat metal disc 20*, which in turn engages against the end of the tube 18, and it is fixed on the tube 18 by means. of indentations 21 forced by a suitable tool into the fibre of the tube. The blade 16 extends through a slot in the flat head and has spaced extensions 16 which extend through holes in the disc 20 and are riveted against the inner face of said isc.

The other head 19 is made in two separable parts, (see Figures 6 and 9) namely, a short tube 19, which is permanently attached to the fibre tube 18 in the manner just described in connection with the other head, and a flat, circular disc 19*, which fits snugly within the open end of said tube, against the end of the fibre tube, beyond which the short metal tube 19*- extends. The disc has diametrically opposite ears 19, 19 which embrace the tube 19 and are secured thereto by screws,the metal of the tube being upset through the fibre tube 18 and tapped to receive said screws. The projecting end of the metal tube is notched as indicated at 19 to receive the radial extensions of the disc 19 of which the ears are partsthus fixing and determining the angular position of the blade 15, which 1s attached to the disc by riveted extensions 15. From this description it is manifest that the disc 19 is readily removable to open the end of the fuse body for inserting or for removing and replacing a fused cartridge,

- and that it is easily and quickly applied,

with the blade 15 carried by it always in the same plane as the plane of the blade 16 which is permanently fixed to the body.

The fusible member or cartridge 17 is constructed as follows (see Figures 3 and 7) 22 indicates a tube adapted to fit snugly within the body tube 18 and made of insulating fibre material. Said tube constitutes the body of the cartridge and contains any usual insulating powder which surrounds the fusible conductor members in a familiar manner. 23, 24 indicate metallic caps which closethe ends of the tube, and 25, 25 indicate two thin, flat, parallel, fusible blades or bars, the fusible conductors, which extend through the tube 18 and establish electric connection between the. caps 23, 24.

Each cap 23, 24, has a flange 23, 24* adapted to embrace the end of the tube 22. In the head of the tubes are punched a plurality of detents 23", 24*, arranged in a circle and spaced equally within the cap flange in such manner that, when a cap is applied to the end of the tube 22 and its flange is clinched upon the outer surface of the tube, said detents Will grip the inner surface of the tube and the cap will be locked on the tube. (See Figure 5.) I

The fusible bars 25 have holes or openings 25 midway of the length of the tube 22 to determine their effective cross section and are permanently fixed to the one cap 23 as follows :-26 indicates a socket member extending parallel to the central axis of the tube 22 and attached to the head of the cap 23. Both bars 25 are bent at right angles near one end, as indicated at 25, 25 ,one of said parts 25 being longer than the other to provide a space between the main lengths of the b'ars,and are then bent back into 21 plane parallel to said main lengths. The parts 25", 25", thus offset, are in contact and are gripped, as shown in the socket member, 26, which has the greater part of the length of its tubular wall on one side, 26, collapsed into 'the half cylindrical opposite side 26" so as to engage and securely grip the offset end parts 25 25 of the fusible barsin the space between them-solder be ing used to permanently attach the parts together. (See Figure 6.) The socket member has its other, cylindrical end turned down to provide an annular shoulder 26 and the reduced end is extended through a suitable hole in the head of the cap 23 and is then riveted down against the outer face of said head-thereby rigidly and electrically connecting the socket member 26 and the attached fusible bars 25 to said cap. The inside of said socket end is tapped to receive a screw and its central axis is located in a diametric plane of the tube 22 extending at right angles to the planes of the bars 25. The cap is filled with asbestos 27.

The cap 24, opposed to the one just described, is provided in its head with parallel spaced slots 28 and the bars 25 are made considerably longer than the tube 22, so that when the cap 24 is applied to close its end of the tube said bars extend through said slots, as indicated at 25 (see Figure 3). Each bar is provided with a stud 25 indented or punched in it.- Said studs are located closely adjacent to the head of the cap and are adapted, when the bars are fused and severed at points in their intermediate lengths, to engage said cap, so that the cartridge as a whole may be withdrawn from the body of the fuse by a pull upon the extensions 25.

The intermediate lengths of the fusible bars 25 are preferably reduced in width to provide a core for a heating coil 29 (see Figure 7), mica insulation bars being placed against the outer face of each bar and being arranged to insulate and directly support said coil and prevent its electrical contact with the fusible bars. The ends 29 of the heating coil'are extended through openings in the tube 22 and are connected to longitudinally spaced flat spring contacts 30, 30 (see Figures 2 and 3) attached to the outside of said tube and located in the diametric plane of the tube, which extends between and is parallel to said bars 25. The plane of said contacts is thus at right angles to the diametric plane containing the central axis of the threaded end of the socket 26. 31 indicates the said openings, which are located at equal distances from the ends of the tube 22. Eyelets 32 are inserted into said openings from the inside of the tube and the contacts 30 have each an eye which is engaged upon the end of the e elet, which is then riveted down against t e outer face of the tube 22,-the associated end 29 of the heating coil being brought through the eyelet and a drop of solder used to permanently seal the wire end and eyelet contact together. The contacts 30 extend towards the middle ofthe tube 22 and their main lengths are offset slightly from the body of said tube, to provide for a slight yielding movement.

The fusible member as thus described constitutes an integral cartridge, which may be made up in quantities ready to be supplied on demand, each ready to be inserted in a fuse. Each cartridge will be designed for a certain load, which will be indicated by a stamp 33 on the inside surfaces of the extensions 25, which are aptly designated as tell tale tags. The designed load to be carried by a cartridge is capable of ready variation in cartridges otherwise alike in every way except for the size of the openings 25 in the bars ,25. There being a plurality of bars, in the case illustrated, two bars, the load is divided between them, thus more readily and quickly distributing the heat of their fusion.

Referring back now to the fuse as a whole, and particularly to the wires 13, 13 by means of which its associated heating coil is connected to another circuit: Said wires have ends 13", 13"- (see Figures 2, 4 and 5) inserted into eyelets 13, which are attached in holes formed in the fibre body 18 of the fuse,the eyelets being securely riveted against the wall of the body and the wire end being secured in the eyelet by means of solder. The holes in which the eyelets are engaged are at equal distances from the end of the body 14 and are located in the diametric plane of the blade contacts 15 and 16. The heads of the eyelets 13 present interior contacts 33 which are adapted to engage and make electrical contact with the spring contact brushes 30 when the cartridge 17 is inserted into the body 14, with said contacts in line with and immediately beneath the said eyelets.

In the permanently attached head 20 of the fuse is carried a rotative but longitudinally immovable screw 34 (see Figure 6),

which is adapted to be engaged in the threaded end of the socket 26 in the cap 23 of the cartridge. The head of the screw 34 is provided with a radial flange 34 which is engaged between the disc 20" and the metal of the flat head of the cap 23, which is upset about the hole through which the head of the screw extends,-the shank of the screw extending through a hole in the disc 20 The method of assembling the parts is apparent.

The aforesaid screw 34 is so located in the head 23 that its axis of rotation is placed off center of the head and in that diametric plane of the fuse body which extends at right angles to the diametric plane containing the blades 15,16. It will therefore be manifest that ifthe cartridge be inserted into the fuse body and be adjusted to a position so that the screw 34 may be engaged in the threaded end of the socket, and if the said screw then be rotated until it can be turned no longer, the cartridge will be securely locked within the fuse body with the contacts 33 in proper engagement with the-spring contacts on the cartridge body. This arrangement obviates any danger of error in first loading the fuse or in replacing a burnt out cartridge.

After the cartridge is inserted and locked in the body, as above described, the extension s 25 of the fusible bars are turned back against the cap 24 of the cartridge, so as to extend through the notches 19 in the tube 19* at the open end of the fuse, and are then turned down against the outside of the tube-19, whereupon the head piece 19 is inserted in place with its cars 19 engaged against the exposed faces of said extensions and the screws are applied-elongated holes 25 being provided in the extensions for the passage of said screws. Said extensions are long enough so that the tell tale tags 33 are exposed to View below the ends of the ears 19. The fuse is then ready for use.

In Figure 10 is shown the manner of connecting the fuses in circuit where the conductors are front connected, that is to say where the conductors and terminals are on the front of the board. 11 11 indicate the terminals of the circuit 11, for example, and 11 11 the connected sockets for the blades 15, 16 of the fuse 10. The wires 13, 13 of the heating coil of the fuse 10 have terminals 35, 35 (to which they are attached in a familiar manner), which are connected and held by the same bolts or screws which attach the terminals 11 11 to the board,-the wires 13*, 13 thus connecting the associated heating coil in shunt with the circuit 11.

In order to readily adapt the fuses for use without the necessity of providing the extra terminals 35, the fuse heads, 19, 20, are preferably provided with screws and Washers 36, 36,the screws being threaded through the tubular parts of the heads into the body in a familiar manner and being located in the diametric plane of the blades 15, 16, as shown in Figure 2 (not shown in Figure 5, the same being omitted therein). By means of these screws the wires 13 of the heating coils may be connected in shunt in an adjacent circuit through the heads of the fuses, instead of through the terminals 35.

The operation of thefuses is familiar and needs no description. When the cartridge of the fuse in one circuit is blown by an overload, the current in that circuit is shunted to the heating coil of an adjacent circuit,

. causing the cartridge of the fuse in that circuit tofuse,'whereupon the current of the second circuit is shunted to the heating coil in the fuse in the third circuit, causing the cartridge therein to fuse,thus breaking the connection in all three circuits.

In order to relieve the pressure developed in the cartridge when the fusible element is fused, the heads of the cartridge are provided with openings to permit the escape of the gases formed by the fusion and the heads of the fuse are also provided with openings to permit the escape of said gases to the at-' iuosphere, thereby relieving the pressure within the fuse. 37, 38 (see Figures 6 and 8) indicate openings in one head of the fuse, namely, in the fuse head and the disc 20, and indicates (see Figure 9) the openings in the other end of the fuse. 4O indicates the openings in the heads or caps of the cartridge.

I claim as my invention 1. In a fuse for multiphase circuits, in combination with a fuse body, a removable cartridge containing a fusible element and a heating element associated therewith, contacts fixed on the outer surface of said cartridge and connected through the wall of said cartridge with said heating element, terminals fixed in and extending through the body of said fuse and adapted for engagement with said contacts, means for securing said cartridge in said fuse body adapted to insure the engagement of said contacts and terminals upon the insertion of the cartridge, and conductors connected to said terminals.

2. In a fuse for multiphase circuits,in combination with a fuse body, a removable cartridge having a tubular insulating body and containing a fusible element and a heating element associated therewith, spring the insertion of the cartridge, and conductors connected to said terminals.

3. In a cartridge for an electric fuse, an insulating body and a closure for the end of said body consisting of a tubular metal head, the flat end wall of said head being provided with a plurality of circularly disposed detents cut from the metal of the head and bent inwardly, said detents being spaced from the periphery of said head and being adapted to engage within the end of said body when the tubular part of said head is clamped upon the outside of said body.

4. In an electric fuse, an insulating tubular body, a fiat metal disc adapted to be engaged against one end of said body, a metal head having a tubular part adapted to be fixed on said insulation body and having a substantially flat, slotted end adapted to engage against said disc, and a blade contact adapted to extend through the slotted end of said metal head and having an extension adapted to be riveted in said disc.

In testimony that I claim the foregoing as my invention, I afiix my signature, this 15th day of August, A. I). 1921.

ELMER L. OGLE.

Witnesses:

, CLARENCE E. MEHLHOPE,

T. H. ALFREDS. 

